I. Technical Field
The present invention relates to a cooling storage, which comprises multiple evaporators and supplies a refrigerant to these evaporators from one compressor.
II. Description of the Related Art
As one of this kind of cooling storages, for example, Japanese Unexamined Patent Publication No. 2002-71245 has been disclosed, in which heat insulating freezing room and refrigeration room are partitioned in a heat insulation storage body, while an evaporator is provided in each room, so that a refrigerant is alternately supplied to each of these evaporators from one compressor to produce cooling action.
In this kind of refrigerating cycle of a refrigerator, a refrigerant is compressed by the compressor and then liquefied by the condenser, so as to be alternately supplied to the evaporator for freezing room and the evaporator for refrigeration room that are connected to the exit side of a three-way valve respectively via a capillary tube. The operation of the compressor is stopped on condition that both freezing room and refrigeration room are cooled down to the lower limit set temperature, and when any one of them then exceed the upper limit set temperature, the compressor is restarted.
A commercial refrigerator, which is used in conditions where its door is frequently opened and closed and the ambient temperature is high, is needed to be designed considering possibility of a rapid rise of the temperature within the rooms during stoppage of the compressor. Therefore, in this kind of refrigerator, when the operation of the compressor is stopped, the high/low pressure difference between the sucking side and the discharging side of the compressor needs to be eliminated as soon as possible (restarting the compressor with the a large pressure difference causes an overload of the compressor). For this purpose, the three-way valve is operated so that both the entrance sides of the evaporators for the freezing room and the refrigeration room and the condenser side are interconnected with each other, and thus, the refrigerant remained in one evaporator is poured into the other one, eventually, the high/low pressure difference is eliminated quickly.
However, according to the above-mentioned method of interconnecting both evaporators for eliminating the high/low pressure difference right after stopping of the compressor, it has been a problem that the refrigeration room side may be in a supercooled state in a situation where the ambient temperature is low like, for example, in the winter season. The causes are as follows.
For example, in a situation where the preset temperature of the refrigeration room is 3 degrees while that of the freezing room is −20 degrees, and when the ambient temperature reaches a low temperature around 5 degrees, it is hardly necessary to cool the refrigeration room due to the extremely small temperature difference between the inside and the outside of the refrigeration room. This means that the compressor repeats the operation and stops the operation so as to cool only the freezing room. In other words, when the inside of the freezing room exceeds the preset temperature, the compressor is started to supply a refrigerant to the evaporator for freezing room. In response to this, when the inside of the freezing room is cooled to the preset temperature or lower, the compressor is stopped, and at the same time, both the evaporators are interconnected by the three-way valve, so as to eliminate the high/low pressure difference of the compressor. After that, when the inside of the freezing room reaches the preset temperature or above, the compressor is restarted, and thus, the cycle for supplying a refrigerant again to the evaporator for freezing room is repeated by switching the three-way valve.
During this cooling operation, while the compressor is in operation, the three-way valve cannot be switched to supply the refrigerant to the evaporator for refrigeration room. However, after stopping the compressor, the three-way valve is switched to the interconnected state of both evaporators due to the pressure balance, causing the liquid refrigerant being supplied to the evaporator for freezing room to be supplied to the evaporator for refrigeration room through the three-way valve. The liquid refrigerant therefore produces cooling action when gradually evaporating due to the eliminating of the pressure balance. Moreover, when the inside of the freezing room exceeds the preset temperature, the liquid refrigerant also produces cooling action by evaporating at the time of restart of the compressor. As mentioned, according to the conventional refrigerator-freezer, the refrigeration room may be supercooled even without supply of a refrigerant to the evaporator for refrigeration room during the operation of the compressor.
The present invention has been completed based on the above circumstances, and its purpose is to provide a cooling storage, in which from one compressor a refrigerant is selectively supplied to multiple evaporators, preventing one evaporator side from becoming a supercooled state.